Process for the table agglomeration concentration of ore



Jan. 2, 1951 1.. F. HEWETT ET AL 2,536,286

PROCESS FOR THE TABLE AGGLOMERATION CONCENTRATION OF ORE 2 Sheets-Sheet 1 Filed Sept. 4, 1947 Ill Ill

R E N 0 m 0 N 0 Gausf/ c Fahyacid Fuel 0/! Conditioned pulp DISTR/BUTOR Enrichedpu/P TABLE FEED LAU/VDER D, M A 65 m U p m m f b 0 m d 8 m 9 k L. F. HEWETT ET AL PROCESS FOR THE TABLE AGGLOMERATION CONCENTRATION OF ORE Jan. 2, 1951 2 Sheets-Sheet 2 Filed Sept. 4, 1947 Patented Jan. 2, 1951 UNITED STATES PATENT orrl-ce PROCESS FOR .THE TABLE KAGGLDMERA- TION CONCENTRATION OF ORE Louis Hewett, Bartow, man, and "Charles ileinrichaiflichmmld, Va., assignors to Virginia Uarolina Chemical Corporation, Richmond, Va acorporationof Virginia Application September 4, 19547, Serial-No. "772,070

table agglomeration concentration of ore :matetrial, the usual procedure "is to "first prepare the ore for 'tabli-n g by agitating 'a thick pulp of the material containing gangue with the proper proportions of selective conditioning and agglomerrating reagents, such as for example caustic, fatty acid and f-uel oil such a'manner as to condition the pulp and to encourage the formation of loosely bonded agglomerates of 'mineral values 2 Claims.

man and 'Liittieford. 'When properly conditioned 1 feed of this 'pulp'is supplied to such tables "some of the mineral values being in the form of aggl-omerates containing air bubbles, travel across the riffles and are discharged along the lower long edge of the table as a concentrate. mineral particles being coated with oils travel in the same direction in the form of a shin float, riding on the surface of the water. The gang-us, which may consist principally of silica sand or other "material is progressed in a direction par- :allel to the ri-flles and forms a lower-layer on the deck of the table between the riifies. "This sand is discharged from the narrow end of the tables furthest from the head end. The capacity of *such tables is limited by their ability to effect the physical separation and discharge of the sand 'gangue.

The primary object of our invention is to provid'e means for greatly increasing the capacity of the shaking tables terms of tons of ore pulp handled e-fiiciently per hour of operation. i i second object the provision of means'where'by the metallurgical recovery of 'a higher grade product is substantially increased.

These ob'j acts are accomplished by our method in which the tables are assisted in separa'ti-ng and discarding gang-ue sands by means of a "partial concentration of the mineral "values before the feed is ever introduced onto the table, thereby "reducing "the amount oiwork which "must be done #57 per cent concentrates is anproxmately double the value :of .68 or 69 per cent concentrates.

in table agglomeration'concentratton of ore's'it Other is customary to use several tables. Conditionin for all tables may ?be done in a single conditioner and the conditioned feed continuously discharged into .a distributor which (continuously divides the total feed into equal parts. Each part .is :conveyed by a separate table teed launder :by gravity to the feed box of one of the tables.

It has now been found that not only is the Ao'iled zmaiterial levitated more readily than the unoiled sand, flout "that the effect 'ibecomes so pronounced ado-ring travel of the pulp through the launder that a partial separation may be accomplished in the launder by providing means whereby the upper "stratum of pulp may :be substantially :sep-

arated from the "lower stratum. 'That is to :say,

when a monditioned pulp moves in a launder or pipe there is a definite tendency for the sand fraction to segregate at :a lower level than the mineral value fraction which "is oiled and :generally associated with air bubbles. We i-hswe tound that "the lower :portion, higher in gangue content, may be :drawn off from the bottom .of the iaunder leaving the upper portion, richer mineral values, remaining in the launder. "We have also found that the tendency tor the roiled :a-nd u-no'iled portions of the pulp to separate in the launder can *be encouraged and assisted by "the use of battles or other devices for causing turbulence in the pulp. Such devices are of particular ibenefit where the total distance travelled lay the pulp flowing in the launder is relatively short. We have further found that by introducing the thus separated portions onto :a shaking table at separateT-eed positions, we can -increase both the capacity of the shaking tables and the efficiency of the concentration operation performedby the tables.

The method of practicing the invention may be more readily "understood lay reference to the drawings in'whicht Fig. T1 is anew sheet-ofthe-preferred procedure,

a is a schematic perspective View of the :ieed launder fits accessories, a part being 'shown'in-section,

table feed launder 3.

substantially unaffected, (12) passing the thus treated ore pulp into launder, (c) accomplishing a preliminary separation of the pulp flowing through thelaunder into two portions, one portion being rich in the desired values while the the invention, it is apparent that the solids must have been previously ground and screened to obtain the optiumum particle size normally em- ;ployedthe practice of table agglomeration separation (200 mesh to 8 mesh) of the particular ore being concentrated. The pulp is then run into a conditioner I.

The conditioner may be of any commercially successful design such as the horizontal rotary type, and conditioning for all the tables may be accomplished by a single unit of suitable size.

The reagents for oiling the ore are introduced into the conditioner, these reagents being identical in nature and quantity to those normally employed for conditioning the particular ore 'prior to concentration by means of a shaking table. The reagents illustrated in the flow sheet; to wit, caustic, fatty acid, and fuel oil, are those generally employed in operations upon phosphate rock.

The conditioned feed is discharged into a distributor 2 which divides the feed into eoual parts, depending upon the number of t bles to be supplied. If it be desired to operate only a single table, of course the distributor 2 may be omitted and the conditioned pulp passed directly from the conditioner I to a table feed launder 3. Asillus- -trated, a six-way distributor may be employed to feed the conditioned pulp in equ l quantities to six table feed launders, each leading to one of six tables. but it is obvious that any desirable number of tabl s may be em loyed in cooperation with a distributor capable of delivering to that number of table feed launders.

introducing the two portions onto- If desired, water may be added in the distributor to insure flow by gravity of the pulp in launder 3.

From the distributor 2. the p lp passes to the The table feed launder may consist of an open square-sided trough or of pipe or of any suitable design providing adequate cross-section for the flow of the conditioned pulp. The pulp is conveyed along the launder by gravity, and simultaneous with the flow of the the result being that the treated pulp flowing in --the launder tends to arrange itself into two separate strata. The upper layer contains most of "the-mineral'values while the lower layer com prises mainly gangue.

It is obvious that up to a certain point, the

pulp toward the lower end of the launder a levitation of the oiled pulp occurs while the unoiled .gangue sands accomplish a settling out eifect,

ing determined by the length of the table feed launder and the angle at which it is mounted. We have made no attempt to establish critical limits for any of these factors, as the maximum efficiency of our process will depend in each case upon the type of ore being concentrated and the particular characteristics of the pulp being handled.

Suflice it to say that at the lower or feed end 4 of the table feed launder 3, a separation of the lower stratum from the upper stratum is accomplished to give two separate cuts of pulp. This separation, which is in effect a partial concentration of the ore, may be accomplished by any suitable means. Properly disposed bafiies may be used to assist the more rapid and com plete formation of an upper layer of pulp rich in the desired mineral values, leaving a lower portion'rich in gangue to continue its flow to the end of the launder. On the other hand, the lower layer high in gangue values may be drawn ofi through the bottom of the launder, leaving an upper portion richer in mineral values to continue its flow to the end of the launder.

In practice, we prefer the latter method, but in any event, the thus separated portions are separately conveyed to a table 5, the portion rich in concentrates being run into table feed box a disposed to introduce pulp onto the table at the upper or feed end of the table while the portion rich in gangue is introduced onto the table by means of feed box 1-disposed near the lower or tailings discharge end of the table.

The preliminary launder separation may be accomplished by any number of simple forms of apparatus, and although the practice of our invention is not limited to any particular form of apparatus, some of the forms which We have found to be operable are illustrated by the drawings.

According to the design illustrated in Fig. 2, wherein a section of feed launder 3 is represented having a receptacle 8 fastened to its under side and opening into the launder as indicated. we have shown that perforations 9 operate to draw off the lower stratum rich in tailings for delivcry to the feed box F via a supplemental-table feed launder I 9. It may be desirable to equip the floor of the launder 3 with transverse rifiles Ii in order to produce tumbling and turbulence in the pulp stream which may in some cases assist in the preliminary separation. The rifiies mayv extend entirely across the floor of the launder or may be disposed in any pattern found to give the desired tumbling or turbulence to a particular ore pulp. In practicing our invention with ores of th type described below, we have found it satisfactory to employ riiiles of about A; inch in height extending across the entire floor of the table feed launder in conjunction with a receptacle of'the type shown, in which the perforations comprise holes having a diameter of approximately A; inch. I The type of device illustrated in Figs. 3 and. 4

consists of a receptacle !2 fastened to the under side of a table feed launder 3, thereceptacle opening into the launder as shown. A supply of water (indicated by I3) is arranged, so as to provide an adjustable jet or stream of water in receptacle !-2. An outlet l4 from receptacle I2 is provided as indicated. In this application of the invention the flow of conditioned pulp is present in the launder at considerable depth (at times as much as 1 inch deep), the sand 'tends to work toward the bottom While the conditioned or oiled ore valuestend to work upward. In the receptacle l2 tendencies are further assisted by the turebulenceacreat'ed 'hy'the water jet and the inci- -=dentalentrapment :of air in the agitated mass. The result is that a .-'substtantial "apart of the settles to the bottom of recepacle l2 and passes through outlet it together with :a relatively "small part of the .ore values. At the same time, conditions in receptacle i=2 are favorable to the invitation of the .ore values, the major portion of which continues down the -launder together with some sand in the direction indicated.

in any event, any form. of apparatus may :be arsed which will accomplish a partial concerr izn-ation or enrichment orthe are by means of a preliminary separation in the table ieediaunder rhefore the feed is introduced onto the table :5; The enriched portion .flows to the feed :box '6 in the usual manner and .is there distributed -1on the .:head end of the deck of the table 5 'where the usual separation of .gan'gue from the concentrate proceeds in the manner already described and-as is Well-known. The portion flowing through the holes '9 and consisting largely of gangue is .led :and delivered to the upper edge of 'the'table :atva

'gpoint nearer the tailings discharge end. The 1 small remaining part of ore concentrate floats across and on top of the :gangue and discharges .into the concentrate collecting launder l5'where- -.as the gangue being already well on its way toward the tailings end of the table and "already 13;

separated from the ore concentrates is progressed by the motion of the table until it discharges into tailings collecting launder H5.

The particular type of table 5 emplo ed is of no importance to our process as long as the proper p degree of concentration is obtained; however, the apparatus which we most favor is the shak ng table of 'the tvpe of the Deist'er diagonal deck :tableor the Wilfley No. 6 table.

While the degree of preliminary concentration not sufficient to give commercial results direct, ,th partial concentration is accomplished by unusually :cheap and simple means and the results of the practice of the process are extremely outstanding. It is apoarent'that any ore amenable to table agglomeration separation will respond in ,-the same manner when concentrated according to o r process, but it will be appreciated by those tallic ores and of their respective ganguesis often 155 identical for all practical purpos s. As regards Florida Pebble phosphate. which was concentrated theexamnles given below, not only is there a practical identity in the specific gravity of the phosphate rock and its silica gangue. but

in the ore-gangue mixture as prepared for table agglomeration separat on, the particle-size of both materials is practically the same. Therefore, further sizing or classification results in no useful concentration and so the separation of the jtwo materials must be made by some means such as .froth flotation or agglomeration tabling.

Inactu'al practicein a phosphate flotat onp'lant :the folio-wing results were obtained in full scale 1 10' 1 commercial operation.

The six primary tables were arranged in two rows of three each. The table feed was conditioned continuously in a rotary conditioner which discharged continuously into a six-way distribull $011. For 'the purposes pf *the test the feed-Flaunders *to the northeast table and to the northwest Ftabie .(located .side'zby :sidei) were equipped "with 'itlie devi'ce described in Figs. .3 and .4 and so far:- =ranged that the devices could be .bl'an'ked off at will.

In the first test, the device on the northeast table launder wastin operation, but "the dcviceon the northwest ta'bielaunder was not in operation. Samples were taken simultaneously from both tables which were in continuous operation and receiving feed prepared and distributed as described above. In the second test the device =on the northwest table launder was in operation, but the device on the northeast table was not in "operation.

Test 1 Northeast "Northwest Table-Device TahleeDe-vice' Operating 3 v, Not Operating :aan i 111501.; B. RL lnsol.

54.96. 30.03= ConditionedFeed.... 5322 321195 38.78 13.81 5 Discharge 8t 6.

29.263 61.580; Discharge-from:

16.18 4.02. Conccntmtesv -10. 28 V 85.60; "Fails 1 Bone phosphate of lime.

Test .2

North east Table-J 1 Northwest Tahle Device Not Deviice'op'erat Operating 1 Zing :aze. FL]. lnsol. 313.311.. 'rnsoi.

'C' ntiitioned Feed...... ...j 59.500. 24.298 lscharge at .6. 61.80 .21. 42 'Disc'nargc l'roml4 20106 72:71 Concentrates... 76. 41 3. 88 'Iai1s 7. 75 S8. 85 B. P. L. 'Rcc'Ove 96. 5%

Test data for the same two tables were taken again and indicate clearly the improved perform-- -':ance of "the tables when the invention is prac- Northeast Tam Dcv icc f i Operating 'Northwest Table-Defies N 0t Operaing- Insol.

Conditioned Beulah"-..

Discharge at 6 -76. -.Concentratcs.

8X30 Tails 05. B. P. L. Recovery .Test 4 lorthwestflahlev X j Device TQ'pera't- .flpeiafiiirg L .fing

LB. 17.11.; 'ilns'dl ZB. .E .ZLL Insol.

46. 26 41.83 Conditioned Feed 55. 7O 30. 23 Discharge at 6. 63.56 19. 88 Discharge from 14 23. 38 71. 54 69.33 13.48 Concentrates... 76. 73 3. 84 11. 84. 28 Tails 12. 61 80. 50

89.8% B. P. L. Recovery 92. 6%

of feed.

The above examples illustrate clearly that when the tables are assisted by the method of the invention, a very much higher grade concentrate and a higher metallurgical recovery invariably result. Measurements were made to determine to what extent the capacity of the tables was affected. Experience in the phosphate field shows that the Wilficy No. 6 tables will do excellent work at a feed load of about 1% gross tons per hour per table and may under very favorable conditions do a good job at 2 gross tons per hour In the above detailed tests the tables received a total of 3.83 gross tons per hour of feed each and it was found by measurement that out of this total, 1.66 gross tons per hour were diverted through outlet 14. It was therefore possible to process with excellent metallurgy a tonnage of feed representing more than 90 per cent overload or expressed in other terms the capacity of the tables was nearly doubled.

An additional run was later made using launder separation means similar to that disclosed in Fig. 2, but in this case the apparatus was even more simple than that illustrated. Riilles H and receptacle 8 were not employed. The apparatus was prepared merely by drilling six inch holes in the floor of a table feed launder at a point about three feet from the normally used table feed box 6. The launder H! was arranged to receive the discharge from these holes.

At the time of the test, the conditioned feed in the launder before it reached the holes analyzed 53.29 per cent B. P. L. and 33.70 per cent insolubles. The discharge from the six A; inch holes, amounting to 0.5 gross ton per hour, analyzed 14.83 per cent B. P. L. and 80.80 per cent Insol., indicating that considerable segregation had taken place in the launder. Samples were taken to determine table performance under these conditions with the following results:

Recovery i In this test the inch hole discharge was sent direct to tailings launder without being treated on the table at all. Thus, while it is found that the degree of preliminary concentration accomplished in the launder ordinarily is not sufficient to give commercial results, yet under certain conditions it may be necessary to treat only one of the separated portions on the table thereby increasing the over-all efiiciency of the operation still more.

It will be appreciated from the foregoing that the invention is not limited to any specific means for accomplishing the preliminary separation, but that any means or device which takes advantage "of the jdiiferent levitation tendencies of oiled ore values'and unoiled gangue or which encourages or accentuates these varying degrees of levitation, whether by purely mechanical means or r with the assistance of air in association with the oiled ore values, is capable of greatly increasing the tonnage capacity of a shaking table for the concentration of ore material and at the same time of considerably improving its metallurgical efficiency.

In the claims as well as the specification, for the sake of convenience, the terms ore values," mineral values, desired values, and concentrates have been used as synonomous to describe the material which it is desired to obtain from an ore pulp by concentration. These terms have been used to distinguish from gangue, tails, sand, and gangue sands which terms have been used to describe the undesired content of an ore.

We claim:

1. A process for concentrating a non-metallic ore comprising selectively conditioning an aqueous pulp of the ore for agglomeration tabling on a riiiled shaking concentrating table, forming a flowing stream of said pulp down an incline, continuing the flow of said stream until substantial Stratification takes place in said stream, dividing said stream into two flowing portions, one of said portions consisting of a lower stratum of said stream relatively rich in gangue and the other of said portions consisting of an upper stratum relatively rich in concentrates, continuously normally introducing onto said table the flowing portion consisting of the upper stratum, simultaneously continuously introducing the flowing portion consisting of the lower stratum onto said table at a point nearer the tailings discharge end of said table, simultaneously concentrating both of the thus introduced portions by the action of said table and collecting the concentrates discharged from said table.

2. A method for concentrating a finely divided and sized phosphate ore comprising treating an aqueous pulp of the ore with agents which will selectively condition said ore for a riflled shaking table agglomeration separation, introducing a stream of said pulp into a launder, conducting said stream down said launder by gravity until substantial stratification of solids within said stream has occurred, continuously separating said stream into two flowing portions consisting of an upper portion and a lower portion, delivering said upper portion in normal manner onto a riflled shaking concentrating table, delivering said lower portion onto said table abnormally in the respect that it is delivered nearer the tailings discharge end of the table, tabling both of said portions slmultaneously, and collecting the ore concentrates delivered from said table.

LOUIS F. HEWETT. CHARLES E. HEINRICHS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Ellis Oct. 5, 1943 

1. A PROCESS FOR CONCENTRATING A NON-METALLIC ORE COMPRISING SELECTIVELY CONDITIONING AN AQUEOUS PULP OF THE ORE FOR AGGLOMERATION TABLING ON A RIFFIED SHAKING CONCENTRATING TABLE, FORMING A FLOWING STREAM OF SAID PULP DOWN AN INCLINE, CONTINUING THE FLOW OF SAID STREAM UNTIL SUBSTANTIAL STRATIFICATION TAKES PLACE IN SAID STREAM, DIVIDING SAID STREAM INTO TWO FLOWING PORTIONS, ONE OF SAID PORTIONS CONSISTING OF A LOWER STRATUM OF SAID STREAM RELATIVELY RICH IN GANGUE AND THE OTHER OF SAID PORTIONS CONSISTING OF AN UPPER STRATUM RELATIVELY RICH IN CONCENTRATES, CONTINUOUSLY NORMALLY INTRODUCING ONTO SAID TABLE THE FLOWING PORTION CONSISTING OF THE UPPER STRATUM, SIMULTANEOUSLY CONTINUOUSLY INTRODUCING THE FLOWING PORTION CONSISTING OF THE LOWER STRATUM ONTO SAID TABLE AT A POINT NEARER THE TAILINGS DISCHARGE END OF SAID TABLE, SIMULTANEOUSLY CONCENTRATING BOTH OF THE THUS INTRODUCED PORTIONS BY THE ACTION OF SAID TABLE AND COLLECTING THE CONCENTRATES DISCHARGED FROM SAID TABLE. 